It is useful, and in many locales a building code requirement, that the attic area of a building be provided with a means to permit air exchange. Such ventilation prevents undue heat buildup, which can render the living quarters of the building uncomfortable and impose unreasonable energy requirements for cooling. Proper ventilation of the attic area also tends to preserve the structural integrity of the roof and roof coverings. To accomplish the desired circulation in roof constructions, venting means have been provided in the upper region of the attic area.
It has long been a conventional practice to employ sheet metal vents in and spaced along the peak of a roof, alone or in conjunction with vents in the side walls of the building. In roofs of any substantial length, it is common practice to install one or more sheet metal vents, and not uncommon to provide a powered fan assist to improve air circulation. These means involve a considerable expense, not only for the vents themselves, but in the labor costs incident to their installation.
These shortcomings have been previously recognized. In U.S. Pat. No. 4,280,399, for example, a corrugated roof vent was proposed. This vent extends lengthwise of and is secured to the portions of the roof near the peak. Cap shingles are then secured in place, spaced above the roof portions. Air is thus vented from the attic area through spacing provided by the vent.
In U.S. Pat. No. 4,942,699, assigned to the assignee of the present invention, an improved vent was disclosed in which an opening along the peak of a roof is covered by a matting, or matrix, of randomly convoluted polymeric filaments, heat bonded to a porous sheet material layer. Such a vent permits the flow of ventilating air through the opening and from beneath a row of cap shingles placed on the vent, and can be provided in roll form, for ready installation in any desired length.
U.S. Pat. No. 5,174,076 discloses a roof vent fabricated from a discrete length of injection molded plastic material. While this vent product may provide adequate venting, it suffers from the limitation that, being injection molded, it cannot be fabricated in an indeterminate length suitable for a continuously rolled product. A rolled vent is desirable because it facilitates installation since the vent need merely be unrolled, fastened and cut to length. Another limitation is the cost of manufacturing the injection molded product.
Other ridge cap vents are disclosed in the following U.S. Pat. Nos.: 4,280,399; 4,876,950; 5,094,041; 5,167,579; 5,425,672 and published Great Britain Application 2186898A. An example of non-woven filter material is disclosed in U.S. Pat. No. 4,701,197.
While the products disclosed in the above-mentioned patents may function satisfactorily under certain circumstances, there is a need for a roof vent which can be manufactured efficiently by conventional thermoforming molding equipment and formed into a roll for shipping and subsequent installation.